A lithium-ion secondary battery is composed of a negative polar plate, a positive polar plate, an electrolytic solution and a membrane between the positive and negative polar plates for preventing a short circuit. The positive polar plate and the negative polar plate are formed as a thin plate or a foil. The electrical polar plates and the membrane therebetween are then stacked sequentially or wrapped helically so as to form a battery cell, which is embedded into a battery container made of stainless steel, nickel plated iron, aluminum metal or a stacked flexible package thin film. After electrolytic solution is injected into the battery container, the battery container is sealed and the battery is formed. The electrical conduction between the cell and external components is achieved by a connection between tabs connected to the polar plates and a pole or a cover board.
In prior art, a plurality of tabs on the polar plates are connected with each other by an ultrasonic welding or a metal melting welding, and then conductively connected to one end of a metallic conductor, the other end of which is conductively connected to upper and lower cover boards of a battery shell, so that the tabs of the polar plates are connected with the pole of the battery shell conductively. However, this operation is complex in the battery manufacture. In particular, a splash of metallic particles may occur during the fusion welding, which impacts the safety and performance of the cell seriously. The participation welding may also pull the connection between the tabs and the polar plates due to mechanical vibration and inconvenient operation and influence the battery performance.